Carbonate-haloformate of glycerol and method of producing same



Patented July 27, 1948 UNITED STATES PATENT OFFICE o j o 2,446,145

V CARBONATE- 'HALOFORMATE 0F GLYCEROL AND METHODOF PRODUCING S-AME'Franlilin Stra'imYNorton Center, Ohio, assignor t o fPittsburgh PlateGlass Company, Allegheny County, Pa., a corporation of Pennsylvania NoDrawing. ApplicationNovember 19,:1946,

Serial No. 710,93?

teams. (01. 260- 338) This invention relates to a novel-chloroformate.

In accordance with the present invention a mixed carbonate-chloroformateof glycerol has been prepared wherein two hydroxy groups of the glycerolare esteri'fied by carbonic acid and one :nyaroay-gr-ou "of'theglyc'er'ol is esterified with other inorganic or organic basesandbasic amines (pyridine, Na OH, NazCOs, CaOH, etc.) which 'tendtoreactwith chloroformates to'rem'ove the chlorine therefrom. I

The reaction of the phosgene and glycerol Jis complicate'd'by the factthat these two reactants are essentiallyimmiscible andconsequentlyessentialy no reaction tends to occur .unless special efforts areresorted to in order to secure intimatecontact between thephosgene andglycerol. This contact may be eifected by vigorously agitatingareactionmixture containingthese two reactants and continuing theagitation over a period of severalhoursl Contact of the rectants 1 is.facilitatedand the rate of reacti0n is considerably increased by useofa mutuahsolvent for glycerol and phosgene. A particularlyeffectivesolventior this-purpose is the mixed carbonatechloroformate ester hereincontemplated. Consequently the rate of reactionis' materially increasedafter a concentration of the desired mixed 'esterhas been secured and ingeneral it is desirable to initiate the reaction in the presence ofaninitial aniount of this mixed ester.

Other mutual solvents particularly other norlmally liquid organicchloroformates mayibe used to"faci1itate the reaction. Thus alkylchloro- ,iormates such as methyl, ethyl, n-propyl, n-

butyl or isobutyl chloroformate, alkenyl or alkynyl chloroformates suchas allyl, methallyl, propargyl, cinnamyl chloroformates, etc., or glycoldichloroformates such as diethylene glycol dichlorof-ormate, or aromaticchloroformates such as phenol or resorcinol chloroformates are suitablesolvents for this purpose.

The process may be conducted at temperatures above about 0 butpreferably not in excess of about 60 0. While some reaction can besecured at temperature below 0 0., other chloro formates such asglycerol bis-chloroformate tend to be produced at such temperatures andin any event the reaction is generally unduly slow. Temperatures aboveabout 60 C. are, in general, undesirable because decomposition of themixed esteftends to occur at such "elevated temperatures.

and solvent and adding'gl'ycerol thereto. 'proximat'elytwo moles ofphosgene is required per'zncleiof glyceroland in most casesadditionleast to some'degree'at with a. reflux condenser capable of condensingphosgene gas and returning it Jtothe reaction vessel,."Forexample; theprocess mayfibap'erformed? by introducingboth liquid .phos'gene andglycerol into a reactor .and vigorously agitating the mixture over aperiod of severalihours usually in the presence of amutual solventasabovegde- (scribed; Furthermore the process may be gperformed byestablishing a: pool oflliqilid phosgerie A? of thatwo reactants to thereaction vessellis controlled so? that theglycerol remains. ii -{slightexcess until the"process is essentially complete.

" Some excess phosgene may be added toward the end of the reaction ifdesired in order to increase the yield.

Theppi'oducts securedby the process depend to adgree upon thetemperature of reaction.

Thus glyceryl bischloro formate tends to form to a somedegree at lowtemperature, for example, below 0'Qwhereas'byproducts "of thedecomposition 'ofthe mixed ester are formed at elevated temperaturesabove 60 C. Within the temperature'range ofO to 60 C, the primaryproduct obtained is 2,3-carbonyldioxypropyl chloroformate,althougho't'her isomers of this ester are obtained in small amount.

The following examples are illustrated.

Example I A reaction flask was immersed in a 30 C. water bath and wasprovided with separate inlets for glycerol and liquid phosgene, anagitator and a reflux condenser cooled by a dry ice-acetone mixture. Onemole of glycerol and two moles of liquid phosgene were slowly introducedinto the reaction vessel while vigorously agitating the mixture. Therate of addition of the phosgene was controlled to maintain the reactiontemperature at about 30 C. When addition of the ph-osgene and glycerolwas complete, 0.2 :mole of excess liquid phosgene was added and themixture was allowed to stand with continuous vigorous agitation at 30 C.for about six hours. Thereafter the reaction mixture was dissolved inmethylene chloride, washed four times with water and dried over calcumchloride. The resulting This mixed carbonate chloroformate' is a mobile,slightly viscous liquid which is light yellow to colorless. The productsets to a hard brittle glass when cooled to 20 to 25 C. The liquidcannot be distilled. The mixed ester has an index of refraction 11 of1.4677 and a density,

Although the present invention has been described with reference tocertain details of specific improvements it is not intended that suchdetails shall be regarded as limitation upon the scope of the inventionexcept insofar as included in the accompanying claims. I I 'I claim:

H 1. A mixed carbonate-chloroformate of glycerol wherein two hydroxygroups of the glycerol are esterified by carbonic acid and one hydroxygroup of ,theglycerol-is esterified by chloroformic acid.

2. A mixed carbonate-haloformate of glycerol wherein two hydroxy groupsof the glycerol are esterified by carbonic acid and one hydroxy group ofthe glycerol is esterified by a haloformic acid of the group consistingof chloroformic and bromo- 64 of about 1.5187. It decomposes on heating1 to about 150 C. It reacts with ammonia solu tions at room temperatureto produce 2,3-car- .bonyldioxypropyl carbamate and with amines .such asaniline, stearyl or lauryl ..form the urethanes.

amine, etc., to

Example II Ninety gms. of 2,3-carbonyldioxypropyl chloroiormate preparedin Example I was introduced into a three-neck flask immersed in a 30-40'water bath and provided with an agitator, inlets ,for liquidphosgene andglycerol and a reflux condenser cooled by a dry ice-acetone mixture.Onehalf mole of glycerol and 1.1 moles of liquid phosgene were slowlyintroduced into the flask, the rate of addition of the reactants beingcontrolled to maintain the temperatureof about 30 to 40 C. Afteraddition of the reactants was complete the mixture was allowed to standat 30 C. with continued agitation for eight hours and was degassed byheating about 90 C. for 15 minutes. The product was dissolved inmethylene chloride and washed and purified by distillation of thesolvent as in Example I. A 97% yield of the mixedcarbonate-chloroformate ester ofglycerol was secured.

While the invention has been desired with par ticular. reference to theproduction of chloroformates it is not limited thereto since othercorresponding haloformates may be prepared in the same manner. Forexample, the corresponding bromoformate may be prepared by substitutionof carbonyl bromide in lieu of phosgene in the above described processwith the consequent production of the compound CH2-CHCHi-0- C-Br and itshomologues.

formic acids.

7 y 3. The compound CH,CHCHg-0-O-Ol 4. A method of preparing a mixedcarbonatechloroformate of glycerol which comprisesmaintaining phosgeneand glycerol substantially in the proportion or two mols 0f phosgene permol of glycerol in intimate contact at a temperature of 0 to C. untilthe carbonate-haloformate com pound has been formed.

5. A methodof preparing a mixed carbonatechloroformate of glycerol whichcomprises react- "ing glycerol and phosgene in the presence of a mutualsolvent therefor at a temperature above 0 C. and below the temperatureat which substantial decomposition of the mixed carbonate-chloroformatetends to occur.

'6. A method of preparing a mixed carbonatechloroformate'of glycerolwhich comprises reacting glycerol and phosgene in the presence of anorganic chloroformate at a temperature of 0 to 60 7. A method ofpreparing a mixed carbonatechloroformate of glycerol which comprisesreacting glycerol and phosgene substantially in' the proportion of twomols of phosgene per mol of glycerol in the presence of2,3-carbonyldioxypropyl chloroform-ate.

- FRANKLlN STRAIN.

REFERENCES CITED 7 The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Name Date Strain Apr. 2, 1946 Number

